1. Field of the Invention
The present invention relates to a method of driving an AC-type plasma display panel (hereinafter, also referred to as xe2x80x9cAC-type PDPxe2x80x9d) in which adjacent two scanning lines share one sustain discharge electrode and a discharge separator for separating surface discharges in discharge cells of the adjacent scanning lines is provided, and a plasma display device which drives the AC-type PDP by using the driving method.
2. Description of the Background Art
An AC-type PDP having a structure in which adjacent two scanning lines share one sustain discharge electrode is well known. The AC-type PDP having such a structure is disclosed in Japanese Patent Application Laid Open Nos. 2-220330 (1990), 6-289809 (1994) and the like. In such an AC-type PDP, when there are 2N scanning lines, only (2N+1) sustain discharge electrodes are needed.
In general, each sustain discharge electrode includes a transparent electrode and a bus electrode. The transparent electrode has a strip-like shape and the bus electrode is provided on the transparent electrode along a central axis in a width direction of the transparent electrode.
A front substrate and a rear substrate of the AC-type PDP are provided face to face with each other with a plurality of stripe-shaped barrier ribs (also simply referred to as xe2x80x9cribsxe2x80x9d) extending in a direction of intersecting the sustain discharge electrodes interposed therebetween. In this case, the discharge cells are defined by the barrier ribs in a longitudinal direction of the sustain discharge electrode, i.e., a direction of intersecting the scanning lines.
As discussed above, in the AC-type PDP of the background art, adjacent two scanning lines share one sustain discharge electrode. Therefore, if there is no structure to separate a surface discharge between two sustain discharge electrodes defining one scanning line from a surface discharge in the adjacent scanning line, the surface discharge generated in the discharge cell belonging to one of the scanning lines has an effect on the other scanning line. For example, a discharge cell which should not be illuminated is illuminated.
The present invention is directed to a method of driving an AC-type plasma display panel. According to a first aspect of the present invention, in the method of driving an AC-type plasma display panel, the AC-type plasma display panel comprises: a first substrate including a plurality of sustain discharge electrodes extending in parallel with one another, between adjacent two of which each of a plurality of scanning lines is defined, each of the sustain discharge electrodes is shared by adjacent two of the scanning lines, and a dielectric layer covering the sustain discharge electrodes, the dielectric layer having a main surface on which surface discharges are generated, the surface discharges illuminating discharge cells belonging to each of the scanning lines; a second substrate provided on a side of the main surface of the dielectric layer face to face with the first substrate, the second substrate including a plurality of address electrodes provided in a direction to intersect the sustain discharge electrodes, the address electrodes extending in parallel with one another; a plurality of barrier ribs provided between the first and second substrates, in parallel with the address electrodes; and a discharge separator provided on a boundary of the adjacent two scanning lines, for separating the surface discharges in the discharge cells belonging to the adjacent two scanning lines, and in the method of the first aspect, one screen is divided into a plurality of sub-fields, each of the plurality of sub-fields including a reset period for erasing electric charges accumulated in the discharge cells; a writing period for performing sequentially a selection of the scanning lines by applying scanning-line selection voltages of different values to adjacent two of the sustain discharge electrodes to scan the scanning lines and performing a writing operation in synchronization with the selection of the scanning lines, in which voltages according to ON/OFF states of image data of a selected scanning line are applied to the address electrodes, to generate a writing discharge in the discharge cell belonging to the address electrode to which the voltage corresponding to the ON state is applied; and a sustain period for performing a discharge sustain operation in which a sustain voltage is applied to the sustain discharge electrodes, to generate the surface discharge in the discharge cell in which the writing discharge is generated, and the electric charges are erased enough in all of the discharge cells belonging to the adjacent two scanning lines in the reset period, the scanning lines are divided into a plurality of groups and the writing operation is performed on a group-by-group basis in the writing period, and the discharge sustain operation is performed on all of the discharge cells belonging to the adjacent two scanning lines in the sustain period.
According to a second aspect of the present invention, in the method of driving an AC-type plasma display panel according to the first aspect, assuming that one of the sustain discharge electrodes shared by the adjacent two scanning lines is a first sustain discharge electrode, one of the sustain discharge electrodes defining one of the adjacent two scanning lines with the first sustain discharge electrode is a second sustain discharge electrode and one of the sustain discharge electrodes defining the other of the adjacent two scanning lines with the first sustain discharge electrode is a third sustain discharge electrode, a potential difference of the second sustain discharge electrode to the first sustain discharge electrode at selection of the one of the adjacent two scanning lines and a potential difference of the third sustain discharge electrode to the first sustain discharge electrode at selection of the other of the adjacent two scanning lines are made reverse in polarity to each other.
According to a third aspect of the present invention, in the method of driving an AC-type plasma display panel according to the first or second aspect, a discharge inhibition voltage for inhibiting generation of the writing discharge is applied to at least one of the two sustain discharge electrodes defining the scanning line when the corresponding scanning line is not selected in the writing period.
According to a fourth aspect of the present invention, in the method of driving an AC-type plasma display panel according to the third aspect, the scanning-line selection voltage is applied to the other of the two sustain discharge electrodes during a period from the start of the scanning on the group to which the corresponding scanning line belongs to at least the end of the selection of the corresponding scanning lines.
According to a fifth aspect of the present invention, in the method of driving an AC-type plasma display panel according to the third or fourth aspect, the scanning lines are divided into the groups so that the scanning lines belonging to the same group are not adjacent to one another, and the discharge inhibition voltage is applied to the sustain discharge electrode defining the scanning line, belonging to the groups not to be scanned, which is adjacent to the other of the two sustain discharge electrodes, during the scanning on the group to be scanned.
According to a sixth aspect of the present invention, in the method of driving an AC-type plasma display panel according to the fifth aspect, the scanning-line selection voltage is continuously applied to the other of the two sustain discharge electrodes during the scanning.
According to a seventh aspect of the present invention, in the method of driving an AC-type plasma display panel according to any one of the first to sixth aspects, the polarity of electric charges is reversed, the electric charges being produced by the writing discharge and accumulated above each of the sustain discharge electrodes of the discharge cells belonging to one of the adjacent two scanning lines, in which the writing discharge is generated, and the other of the adjacent two scanning lines is thereafter selected.
According to an eighth aspect of the present invention, in the method of driving an AC-type plasma display panel according to any one of the first to sixth aspects, a voltage applied to the sustain discharge electrodes is not changed from the end of the scanning on one of the groups when the scanning on others of the groups starts.
According to a ninth aspect of the present invention, in the method of driving an AC-type plasma display panel according to any one of the first to eighth aspects, a voltage applied to the sustain discharge electrodes is not changed from the end of the writing period when the discharge sustain operation in the sustain period starts.
According to a tenth aspect of the present invention, in the method of driving an AC-type plasma display panel according to any one of the first to ninth aspects, the order of execution of the writing operation in the groups is not the same through a plurality of screens.
According to an eleventh aspect of the present invention, in the method of driving an AC-type plasma display panel according to any one of the first to tenth aspects, the scanning lines are divided into two regions in a direction of arrangement and each of the address electrodes consists of two electrodes which belongs to the two regions, respectively, being electrically separated in the AC-type plasma display panel, and the scanning lines belonging to each of the regions are divided into a plurality of groups and the writing operation is performed on a group-by-group basis, and the selection of two of the scanning lines adjacent to each other with a boundary of the two regions interposed therebetween is performed in synchronization in the writing period.
The present invention is also directed to an AC-type plasma display device. According to a twelfth aspect of the present invention, the plasma display device comprises: an AC-type plasma display panel; and a driving device for driving the AC-type plasma display panel, wherein the AC-type plasma display panel comprises a first substrate including a plurality of sustain discharge electrodes extending in parallel with one another, between adjacent two of which each of a plurality of scanning lines is defined, each of the sustain discharge electrodes is shared by adjacent two of the scanning lines, and a dielectric layer covering the sustain discharge electrodes, the dielectric layer having a main surface on which surface discharges are generated, the surface discharges illuminating discharge cells belonging to each of the scanning lines; a second substrate provided on a side of the main surface of the dielectric layer face to face with the first substrate, the second substrate including a plurality of address electrodes provided in a direction to intersect the sustain discharge electrodes, the address electrodes extending in parallel with one another; a plurality of barrier ribs provided between the first and second substrates, in parallel with the address electrodes; and a discharge separator provided on a boundary of the adjacent two scanning lines, for separating the surface discharges in the discharge cells belonging to the adjacent two scanning lines, and in the plasma display device of the twelfth aspect, the driving device drives the AC-type plasma display panel with one screen divided into a plurality of sub-fields, each of the sub-fields including a reset period for erasing electric charges accumulated in the discharge cells; a writing period for performing sequentially a selection of the scanning lines by applying scanning-line selection voltages of different values to adjacent two of the sustain discharge electrodes to scan the scanning lines and performing a writing operation in synchronization with the selection of the scanning lines, in which voltages according to ON/OFF states of image data of a selected scanning line are applied to the address electrodes, to generate a writing discharge in the discharge cell belonging to the address electrode to which the voltage corresponding to ON state is applied; and a sustain period for performing a discharge sustain operation in which a sustain voltage is applied to the sustain discharge electrodes, to generate the surface discharge in the discharge cell in which the writing discharge is generated, and the driving device erases enough the electric charges in all of the discharge cells belonging to the adjacent two scanning lines in the reset period, divides the scanning lines into a plurality of groups and performs the writing operation on a group-by-group basis in the writing period, and performs the discharge sustain operation on all of the discharge cells belonging to the adjacent two scanning lines in the sustain period.
(1) In the driving method of the first aspect of the present invention, in each sub-field, predetermined operations are performed on all the discharge cells in the reset period and the sustain period. In other words, the reset period and the sustain period are not provided for each writing operation of the scanning lines on a group-by-group basis. Therefore, it is possible to remarkably reduce the time required for the reset period and sustain period for one sub-field as compared with a case where the reset period and sustain period are provided for the writing operation performed on a group-by-group basis. Accordingly, by assigning the reduced time to the writing period, it is possible to generate the writing discharge with more stability and more reliability.
Further, since the erase operation is performed on all the discharge cells in the reset period, only one reset period is provided for one sub-field. Therefore, it is possible to reduce the dark luminance (background luminance) and enhance the display contrast as compared with a case where the reset period is provided for the writing operation performed on a group-by-group basis.
Furthermore, since the discharge sustain operation is performed on all the discharge cells in the sustain period, only one sustain period is provided for one sub-field. Therefore, it is possible to remarkably reduce the reactive power in the whole sustain period as compared with a case where the sustain period is provided for the writing operation performed on a group-by-group basis.
(2) In the driving method of the second aspect of the present invention, when one or the other of the scanning lines sharing one sustain discharge electrode is first selected, even if an opposite discharge (unnecessary opposite discharge) is generated between the sustain discharge electrode and the address electrode in the discharge cell belonging to the scanning line not to be selected, the writing discharge can be reliably generated at the selection of the scanning line not to be selected.
Further, in the process of selection of one or the other of the scanning lines sharing one sustain discharge electrode, the polarities of the voltages working between the one sustain discharge electrode and its adjacent sustain discharge electrode can be made reverse to each other. Therefore, it is possible to suppress migration between the adjacent sustain discharge electrodes through the whole writing period.
(3) In the driving method of the third aspect of the present invention, since the discharge inhibition voltage is applied to at least one of the two sustain discharge electrodes defining the scanning line when the scanning line is not selected, the writing discharge (and even the opposite discharge (unnecessary opposite discharge and unintentional opposite discharge) between the address electrode and the sustain discharge electrode, which induces the writing discharge) is not unintentionally generated. Therefore, it is possible to inhibit the normal writing discharge from being impeded by the electric charges generated and accumulated by the unintentional writing discharge and the normal (wall) charges accumulated after the normal writing discharge from being reduced by the unintentional writing discharge. As a result, disadvantages such as not-lighting in the sustain period are solved and an image display of higher quality can be achieved.
(4) In the driving method of the fourth aspect of the present invention, since the scanning-line selection voltage is applied to the other of the sustain discharge electrodes defining the scanning line at the selection of the scanning line, the scanning line can be selected only by switching the voltage applied to the one of the sustain discharge electrodes from the discharge inhibition voltage to the scanning-line selection voltage. Therefore, it is possible to speed up the response of generation of the writing discharge and generate the writing discharge with more reliability as compared with a case where the voltages applied to both the one and the other of the sustain discharge electrodes are switched to the scanning-line selection voltage. Further, the driving sequence of the circuit for supplying the sustain discharge electrode with the voltage is simplified and the load on the circuit can be reduced.
(5) In the driving method of the fifth aspect of the present invention, the discharge inhibition voltage is applied to the sustain discharge electrode defining the scanning line belonging to the group not to be scanned and being adjacent to the other of sustain discharge electrodes during the scanning of the group to be scanned. On the other hand, the discharge inhibition voltage is applied to the one of the sustain discharge electrodes when the scanning line is not selected during the scanning. In other words, the other of the sustain discharge electrodes is sandwiched by the sustain discharge electrodes to which the discharge inhibition voltage is applied other than when the scanning line is selected. Therefore, even if the scanning-line selection voltage is continuously applied during the scanning of the other of the sustain discharge electrodes, no unintentional writing discharge is generated in the discharge cells belonging to the scanning lines sharing the other of the sustain discharge electrodes. Accordingly, by setting the voltage applied to the other of the sustain discharge electrodes as above, the necessity of switching the voltage applied to the other of the sustain discharge electrodes is eliminated during the scanning. As a result, the driving sequence of the circuit for supplying the sustain discharge electrode with the voltage is simplified and the load on the circuit can be reduced as compared with the driving method of the fourth aspect.
(6) In the driving method of the sixth aspect of the present invention, it is not necessary to switch the voltage applied to the other of the sustain discharge electrodes during the scanning. Therefore, the driving sequence of the circuit for supplying the sustain discharge electrode with the voltage is simplified and the load on the circuit can be reduced as compared with the driving method of the fifth aspect.
(7) In the driving method of the seventh aspect of the present invention, after reversing the polarity of the electric charges generated and accumulated above the sustain discharge electrodes defining one of the adjacent two scanning lines by the writing discharge, the other scanning line is selected. Therefore, it is possible to remarkably suppress generation of the discharges in the discharge cells after the writing operation by superimposing the predetermined voltages applied to the sustain discharge electrodes at the selection of the other of the two adjacent scanning lines: on the voltage by the normal electric charges accumulated in the discharge cells in which the writing discharge is generated, belonging to the one of the scanning lines. Accordingly, it is possible to reliably inhibit the writing discharge (unintentional writing discharge) which is unintentionally generated in the discharge cells belonging to the other of the scanning lines by the priming effect of the discharge. As a result, disadvantages such as not-lighting are solved and an image display of higher quality can be achieved as compared with a case where the polarity reverse is not made.
(8) In the driving method of the eighth aspect of the present invention, it is possible to reduce the number of switching operations for the voltage applied to the sustain discharge electrode as compared with a case where the voltage applied to the sustain discharge electrode is set to the predetermined initial value every time before the start of scanning the groups. Therefore, the driving sequence of the circuit for supplying the sustain discharge electrode with the voltage is simplified and the load on the circuit can be reduced.
(9) In the driving method of the ninth aspect of the present invention, it is possible to reduce the number of switching operations for the voltage applied to the sustain discharge electrode as compared with a case where the voltage applied to the sustain discharge electrode is set to the predetermined initial value before the start of the sustain period. Therefore, the driving sequence of the circuit for supplying the sustain discharge electrode with the voltage is simplified and the load on the circuit can be reduced.
(10) In the driving method of the tenth aspect of the present invention, it is possible to inhibit the instability of display which may be caused in a case where the order of performing the writing operation in a plurality of groups is the same through a plurality of screens. Further, even if there arises a difference in the number of luminescences or in luminescence intensity among the groups caused by the writing operation performed on a group-by-group basis in the sustain period, the difference in luminescence intensity can be compensated on a macro time-scale to suppress the luminance unevenness of display image. As the result of these functions, an image display of higher quality can be achieved.
(11) In the driving method of the eleventh aspect of the present invention, two scanning lines which are adjacent to each other with the boundary of the two regions interposed therebetween are selected in synchronization with each other. Therefore, it is possible to suppress variation of the state of the electric charges accumulated in the discharge cells, which may be caused in a case where the timings of selecting the two scanning lines are different from each other. This allows the writing operation to be reliably performed in the discharge cells belonging to both. the scanning lines. As a result, the effects of the first aspect (1) to the tenth aspect (10) can be produced also in the AC-type plasma display panel of the eleventh aspect.
(12) In the plasma display device of the twelfth aspect of the present invention, the same effect as that of the first aspect (1) can be produced.
A main object of the present invention is to provide an AC-type PDP in which adjacent two scanning line share one sustain discharge electrode and a discharge separator for separating surface discharges generated in discharge cells of the adjacent scanning lines from each other, and to provide a method of driving the AC-type PDP.
In particular, a first object of the present invention is to provide a method of driving the AC-type PDP having the above structure, which produces effects of enhancing the display contrast, reducing reactive power and stabilizing the writing discharge.
Further, a second object of the present invention is to provide a method of driving the AC-type PDP having the above structure, which produces an effect of achieving an image display of higher quality as well as achieves the first object.
Moreover, a third object of the present invention is to provide a method of driving the AC-type PDP having the above structure, which produces an effect of reducing the load on the circuit for supplying the sustain discharge electrode with a voltage as well as achieves the first object.
Furthermore, a fourth object of the present invention is to provide a method of driving the AC-type PDP having the above structure, which produces an effect of speeding up the response of generation of the writing discharge as well as achieves the third object.
Moreover, a fifth object of the present invention is to provide a method of driving the AC-type PDP having the above structure, which produces an effect of suppressing the migration between adjacent sustain discharge electrodes as well as achieves the first object.
A sixth object of the present invention is to provide a plasma display device which achieves the first to fifth objects.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.